Biomedical subjects

T Calkavur

Publications and source records attributed to T Calkavur.

9 recordsLinked to original sources

PubMed2002

The effects of L-carnitine on spinal cord ischemia/reperfusion injury in rabbits.

BACKGROUND: Paraplegia after distal aortic aneurysm repair remains a persistent clinical problem. We hypothesized that the tolerance of the spinal cord to an ischemic period could be improved with hypothermic Ringer's Lactate containing L-Carnitine. MATERIALS AND METHODS: Twenty-eight New Zealand white rabbits were used as spinal cord ischemia models. We separated rabbits into four equal groups and clamped each animal's abdominal aorta distal to the left renal artery. We occluded the aortas above the iliac bifurcation for 30 minutes. In group I, the infrarenal aorta was clamped without infusing any solution. In group II, Ringer's Lactate solution was infused at + 25degrees C for 3 minutes at a rate of 5 ml/min into the isolated aortic segments immediately after cross-clamping and the last 3 minutes of ischemia. In group III, Ringer's Lactate solution at +3 degrees C was given in the same method as that of group II. In group IV, Ringer's Lactate solution at +3 degrees C plus 100 mg/kg of L-carnitine was infused using the same technique. We assessed the neurological status of the hind limbs 24 and 48 hours after operation according to Tarlov's criteria. All animals were sacrificed and spinal cords were harvested for histological analyses. RESULTS: The neurological status in groups III and IV was significantly superior to that of groups I and II. All the animals in group I had complete hind-limb paraplegia. Complete hind-limb paraplegia occurred in 5 rabbits in group II. Two of the 7 animals in group III had spastic paraplegia, and none at all in group IV. Histological analysis of the cross-clamped segments of the rabbits with paraplegia in group I, II and III revealed changes consistent with ischemic injury, while findings were normal for the normal animals in group III and IV. CONCLUSIONS: In this model, the infusion of hypothermic Ringer's Lactate contained L-carnitine provided sufficient spinal cord protection against ischemia. Clinically, this may be a useful adjunct for prevention of paraplegia during surgery of the descending aorta.

Animals↗

PubMed2001

Acute intraoperative arterial elongation: an experimental study.

OBJECTIVES: small arterial defects resulting from either trauma or resection of an aneurysm often present difficult problems to the vascular surgeon. DESIGN: to demonstrate that certain arterial gaps as a result of traumatic injury or aneurysm resection could be closed with acute intraoperative arterial elongation. MATERIALS: fifteen mongrel dogs underwent acute intraoperative arterial elongation of the right superficial femoral artery, with the left side used for a control vessel. METHODS: arterial defects created surgically (median 50 (range 25 to 60 mm) mm). Appropriate length of artery was then undermined. A Foley catheter was placed proximally and distally directly beneath this undermined portion of vessel. The vessel is lengthened following 3 expansion/relaxation cycle of Foley catheter. Arterial gaps were closed by end to end anastomosis. Arterial pressure study was performed in all vessels. RESULTS: acutely, arterial pressure differences proximal and distal to the anastomosis were seen only when arterial gaps were exceeded 55 mm. There was no occlusion either acutely or after 4 weeks follow-up period. Light microscopic examination of arterial specimens revealed partial disruption of internal elastic lamina. At the end of the follow-up period, formation of neointima with regeneration of the internal elastic lamina was demonstrated. Scanning electron microscopy revealed minimal endothelial denudation. CONCLUSIONS: we believe that, acute intraoperative elongation can be used as an alternative technique to vein grafting for the repair of small traumatic arterial defects in selected cases.

Animals↗

PubMed2001

An intraaortic solution trial to prevent spinal cord injury in a rabbit model.

OBJECTIVES: to evaluate the effectiveness of an intraaortic delivered solution on preventing spinal cord injury. DESIGN: forty rabbits were allocated into five equal groups. MATERIALS AND METHODS: one clamp was placed just distal to the left renal artery, and another was placed just above the iliac bifurcation for 40 min. Group 1 was not infused (control group). Through a 24G vascular catheter inserted into the isolated aortic segment, 20 ml of LR solution at room temperature (Group 2) 20 ml of LR solution at 3 degrees C (Group 3), and 20 ml of LR solution at 3 degrees C containing 30 mg/kg of methylprednisolone (Group 4) were infused over 3 min. In Group 5, 10 mg/kg of vitamins E and C were delivered two days before the experiment, and 20 ml of LR solution at 3 degrees C containing 30 mg/kg of methylprednisolone, and 10 mg/kg of vitamins E and C was infused at the operation. Postoperative spinal cord function was assessed using Tarlov's criteria. RESULTS: the neurologic status of Groups 3, 4, and 5 was significantly superior to that of Groups 1 and 2. No paraplegia was observed in Groups 4 and 5. Spastic paraplegia occurred in all rabbits of Groups 1 and 2, and in 20% of Group 3. In the electron microscopic evaluation of spinal cord specimens, normal histologic structure was observed in Groups 4 and 5, whereas, some derangements were observed in all others. CONCLUSIONS: intraaortic infusion of a hypothermic blended solution containing methylprednisolone, vitamins C and E provided best protection against postischaemic spinal cord dysfunction.

Animals↗

PubMed2001

Allograft aortic root replacement for aortic valve endocarditis with aortopulmonary fistula.

Acute infective endocarditis affecting the aortic root and valve associated with development of a fistulous communication between the aorta and pulmonary artery was presented in a young Turkish girl. Emergency surgery was required. Operation consisted initially of closure of the defect on the main pulmonary artery with a pericardial patch. This was followed by allograft aortic root replacement.

Adolescent↗

PubMed2001

Coronary artery bypass and carotid endarterectomy: combined approach.

Controversy exists concerning the best management of patients with coronary artery and carotid artery disease. Between June 1994 and July 2000, 88 patients with coronary artery and carotid artery disease underwent combined coronary artery surgery and carotid endarterectomy. Demographics and perioperative variables of these patients were compared with those of 266 patients undergoing isolated coronary artery surgery. Patients in the combined coronary artery bypass grafting and carotid endarterectomy group were elderly patients (p=0.0001) with a higher prevalence of female gender (p=0.0001), left ventricular dysfunction (p=0.006), left main coronary artery disease (p=0.033), triple-vessel coronary artery disease (p=0.002), unstable angina pectoris (p=0.004), and history of prior neurologic events (p=0.0001). Three (3.4%) patients in the combined group and 5 (1.9%) patients in the isolated coronary artery surgery group (p=0.317) developed perioperative myocardial infarction. Two (2.3%) patients in the combined group developed a permanent postoperative neurologic event. Hospital mortality was 5.7% (5 patients) in the combined coronary artery bypass grafting and carotid endarterectomy group and 1.5% (4 patients) in the isolated coronary artery surgery group (p=0.046). Patients with concomitant carotid and coronary artery disease have an advanced arteriosclerosis. Although combined coronary artery bypass grafting and carotid endarterectomy is associated with a higher risk of death and perioperative myocardial infarction than simple coronary artery surgery, this procedure is a preferable approach for these high-risk patients and results in lower neurologic morbidity.

Aged↗

PubMed2001

Cerebral perfusion through separate grafts for repair of acute aortic dissection with torn arch.

We have modified the technique of cerebral perfusion through anastomosed grafts for repair of acute arch dissections that require total arch replacement. We have performed this operation on a 71-year-old man with an acute type-A dissection and an arch tear between the orifices of the brachiocephalic arteries. We used 2 separate grafts for the brachiocephalic arteries and minimized brain ischemia by initiating antegrade selective cerebral perfusion after the 1st anastomosis. The patient had an excellent outcome. This method is simple and provides effective protection. Cerebral ischemic time can be kept under 30 minutes without need of a sophisticated pump setup or a multibranched graft. This affords extra time in case the surgeon encounters an unexpected lesion in the arch.

Aged↗

PubMed2001

[Myocardial protection during coronary artery bypass surgery while off-pump].

Myocardial protection during off-pump coronary artery bypass surgery (OPCAB) is a multifactorial problem and choice of graft sequence, maintenance of stable systemic hemodynamics are of central importance. New devices for atraumatic stabilization of the heart and visualization of coronary anastomoses allow grafting of all coronary arteries without cardiopulmonary bypass. Perfusion-assisted direct coronary artery bypass (PADCAB) techniques, in which coronary perfusion is independent of systemic arterial pressure, can eliminate unstable hemodynamic and improve myocardial protection during complex, multivessel OPCAB.

Coronary Artery Bypass↗

PubMed2001

[Coronary artery bypass re-operations: basic principles].

Mortality and major complications during primary coronary artery bypass operation has decreased substantially during the past 20 years. However, patients undergoing reoperative myocardial revascularization still face markedly elevated perioperative mortality and morbidity. On the other hand, the incidence of reoperative coronary bypass surgery continues to increase. Aggressive perioperative care and optimal myocardial protection is mandatory in these patients. In this article we reviewed the patient profiles, indications for operation, operative techniques and their impact on the surgical results for patients undergoing reoperative coronary artery bypass surgery.

Coronary Artery Bypass↗

PubMed1996

Complement consumption during cardiopulmonary bypass: comparison of Duraflo II heparin-coated and uncoated circuits in fully heparinized patients.

Heparin attachment to synthetic surfaces is one means of improving the biocompatibility of clinically used cardiopulmonary bypass (CPB) circuits. To assess the effect of heparin-coated circuits on complement consumption during CPB, 40 patients undergoing elective myocardial revascularization were prospectively randomized either to a group in which a completely Duraflo II heparin-coated circuit was used for perfusion (heparin-coated Group, n = 20 patients) or to a control group (n = 20 patients) in which an uncoated, but otherwise standard circuit was used. Full systemic heparinization was induced (activated clotting time, 480 seconds) in all the patients included in the study, regardless of which perfusion circuit was used. The two groups did not differ significantly in terms of bodyweight, aortic crossclamp and extracorporeal circulation times. No patient had difficulty in weaning from bypass and the postoperative period was uneventful in all patients. Concentrations of C3 and C4 were found to be within the "normal' range in the prebypass period in both groups. There were no significant intergroup differences with regard to C3 and C4 consumption during CPB. We conclude that Duraflo II heparin-coated circuits have no effect in reducing complement consumption during CPB in fully heparinized patients.

Adult↗